1. Field of the Invention
The present invention relates to an inkjet apparatus.
2. Description of the Related Art
There is known an inkjet apparatus such as an inkjet type printer or a manufacturing apparatus adopting an inkjet technology, which is constructed such that ink supplied from an ink tank is reserved in an ink reservoir (hereinafter, described as sub-tank) provided therein. The ink reserved in the sub-tank is supplied through an ink supply passage to a print head and is ejected on a print medium from the print head to form an image on the print medium. When the ink in the sub-tank is reduced to a value less than a prescribed value, there is a possibility that air enters into the ink supply passage and is then sent to the print head to deteriorate the quality of a print mage. Accordingly, in order that an ink remaining amount in the sub-tank is not reduced below the prescribed value, it is necessary to detect the ink remaining amount in the sub-tank. At the time of detecting the ink remaining amount in the sub-tank, there is a possibility that there occurs an erroneous detection of the ink remaining amount due to foam of ink generated in the sub-tank.
Japanese Patent Laid-Open No. 2006-123365 discloses the technology in which, for preventing the erroneous detection of the ink remaining amount due to the foam of the ink generated in the sub-tank, a liquid surface height in the sub-tank is detected by a plurality of times to enhance detection accuracy in regard to the ink remaining amount. In addition, this publication discloses the technology in which, under a condition where foam of ink tend to be easily generated, the detection of the ink remaining amount is once more performed when a predetermined waiting time elapses after once detecting the ink remaining amount, thus enhancing the detection accuracy thereof.
However, in a case of performing the ink remaining detection in the sub-tank by the method as disclosed in the above publication, even if the predetermined waiting time elapses, the foam in the sub-tank do not possibly disappear. In a case where the foam do not disappear, there is a possibility that the erroneous detection of the ink remaining amount is not avoidable. In addition, in a case of executing a plurality of ink remaining amount detecting processes, since the same process is repeatedly executed, it takes time to complete all of the ink remaining amount detecting processes.